2 TYPES OF BALANCES:

• Electronic — easy and fast to operate. Most common in laboratories. Provides digital measurement readings. Require electrical power, advanced functions include selectable weighing units, selectable weighing modes, computer connectivity for recording and storing measurement data.
• Mechanical — used to teach basic weighing techniques due to their hands-on nature. Do not require electrical power, have a fixed weighing unit, fixed weighing mode and no computer connectivity for recording and storing measurement data.

4 TYPES OF ELECTRONIC BALANCES:

• Toploading — readability between 1mg to 1g. Samples are weighed on top of the instrument, directly above the weighing cell. Capacities can range from grams to kilograms with accuracy of 1mg or 0.1mg. Fast, easy to operate and suitable for most weighing measurements where analytical precision is not required. Because they are not enclosed, they are more susceptible to errors due to drafts and/or vibrations. Applications include GMP, ISO and other quality management systems, basic weighing, dynamic weighing, interval weighing, etc.
• Analytical — readability between 0.01mg and 1mg. Samples are weighed on top of the instrument, but have enclosed weigh pans through the use of draft shields. Applications include differential weighing, interval weighing, formulation weighing, density measurement, pipette calibration, sample management, etc.
• Micro — readability between 1µg and 0.01mg. Applications include stent weighing, particulate matter weighing, pipette calibration, elemental analysis of glass, analysis of pesticides and other critical micro-weighing analyses.
• Ultra-micro - readability of 0.1µg. Applications include particulate matter weighing, ashing or incineration, drying, measurement of coatings, checking spillage quantities and other applications that require the most accurate measurement possible. Ultra-microbalances usually have a maximum capacity of 5 g.

FACTORS TO CONSIDER:

• Capacity — the maximum weight the balance can measure. Choose a balance with 10 to 15% more capacity than your application requires.
• Readability — the smallest change in weight that the balance can detect.
• Calibration — used to ensure that the balance is measuring correctly by comparing measurements of known value. Choose between Manual calibration (using an external weight of known value) or Automatic internal calibration (calibrated automatically with the push of a button through an internal weight).
• Repeatability — the accuracy of the balance in measuring the same weight within a given time.
• Weighing Units — the units of measure that the balance can display.
• Weighing Modes — the balance's ability to perform specialized weighing tasks. Examples of this include percent weighing, parts counting, animal weighing, density determination, etc.